Performance (e.g. efficiency) of an optocoupler is typically evaluated based on current transfer ratio (CTR). CTR is essentially a ratio of output current to input current expressed as a percentage. It is well known that as the voltage rating of the optocoupler increases, CTR decreases. State-of-the-art optocouplers are able to achieve respectable CTRs at low voltages. However, once rated operating voltage reaches a certain level (e.g. above 10 KV), the CTR of these state-of-the-art optocouplers quickly drops to an unacceptable level (e.g. CTR<0.5%). This is attributed to inefficient optical coupling and packaging of these devices.